_ in each district. The colony of Lugdunum was the seat
of the administration, as well as of the imperial cult. No attempt was
made to latinize the three Gauls by the founding of Roman colonies; but
they remained divided into sixty-four separate peoples, called
_civitates_, with a tribal organization under the control of a native
nobility. As early as 27 B. C. Augustus took a census in Gaul, and on this
basis fixed its tax obligations. The rich lands of Gaul were as important
a source of imperial revenue as its vigorous population was of recruits
for the Roman auxiliary forces.

But the Gauls were restive under their new burdens and were in addition
liable to be stirred up by the Germanic tribes who came from across the
Rhine. An invading horde of Sugambri in 16 B. C. defeated a Roman army
and, upon a renewed inroad by the same people in 12 B. C., Augustus
determined to cross the Rhine and secure the frontier of Gaul by the
subjugation of the Germans to the north. The Germans, like the Gauls at
the time of the Roman conquest, were divided into a number of independent
tribes usually at enmity with one another and hence incapable of forming a
lasting combination against a common foe. Individually they were powerful
and courageous, but their military efficiency was impaired by their lack
of unity and discipline.

Drusus, conqueror of the Raeti, was appointed to command the Roman army of
invasion. He first secured the Rhine frontier by the construction of a
line of fortresses stretching from Vindonissa (near Basle) to Castra
Vetera (near Xanten), the latter of which, with Mogontiacum (Mainz) were
his chief bases. Then, crossing the river, in four campaigns (12-9 B. C.)
he overran and subjugated the territory between the Rhine and the Elbe.
His operations were greatly aided by his fleet, for which he constructed a
canal from the Rhine to the Zuider Zee, and which facilitated the conquest
of the coast peoples, among them the Batavi, who became firm Roman allies.
On the return march from the Elbe in 9 B. C., Drusus was fatally injured
by a fall from his horse. His brother Tiberius succeeded him in command
and strengthened the Roman hold on the transrhenene conquests. Drusus was
buried in Rome, whither Tiberius escorted his corpse on foot, and was
honored with the name Germanicus.

*Illyricum and Thrace.* To the east of the Adriatic the Roman provinces of
Illyricum and Macedonia were subject to constant incursions of the
Pann